<template>
  <div>
    <button @click="setNum(1)">+</button>
    <input :value="abc" type="text">
    <button @click="setNum(-1)">-</button>
  </div>
</template>
<script>
export default {
  props: {
    abc: {
      type: [String, Number],
      default: ''
    }
  },
  methods: {
    setNum(step) {
      this.$emit('update:abc', this.abc + step)
    }
  }
}
</script>
<style></style>
